1. Field Of the Invention
The present invention relates to the field of medical imaging, more particularly to the monitoring of a surgical instrument in an operative site.
2. State of the Art
Endoscopic surgery requires a high-performance imaging system for visualization of the operative site, to assist the surgeon during surgery.
A certain number of solutions have been developed to improve the viewing offered by the image of a conventional endoscopic camera.
Some systems use images of the operative site acquired before surgery by any system of CT-scan, magnetic resonance imaging, or stereoscopic camera type. Pre-operative images can effectively be used to segment the 3D volume acquired before surgery to isolate the organs of interest, and to relate them with the per-operative imaging system generally consisting of an endoscopic camera. The merging of the 3D images acquired before surgery with the endoscopic images acquired during surgery provide the surgeon with improved visualization of the operative site since the organs of interest are better highlighted. However, existing solutions are relatively cumbersome to implement. In addition, the images using pre-operative data are not fully reliable since there morphological changes may occur between the acquisition of this data and surgery (whether changes with respect to the inter-positioning of the organs and even changes in shape).
Solutions have therefore been developed based solely on the use of data acquired during surgery to overcome these problems.
For example, it has been proposed to use ultrasound images in addition to endoscopic images, so that it is possible to view organs that cannot be seen by the endoscopic camera since they are hidden. For example, the publication titled: “Real-Time Transrectal Ultrasound Guidance During Laparoscopic Radical Prostatectomy: Impact on Surgical Margins” (Journal of Urology, Vol. 175, 1304-1310, April 2006) proposes using an endorectal ultrasound probe operated by a human operator during radical prostatectomy. This allows a significant improvement in the carcinological results of surgery by providing the surgeon with a precise view of the limits of the organ even if such limits are hidden behind the organs visible in the field of vision of the endoscopic camera. The practitioner therefore has at hand an ultrasound image of the operative site to obtain a very clear view of the organs and their relative positioning, and also has an endoscopic image to view the surgical instrument at the operative site.
To facilitate the surgeon's task, it has been proposed to modify the surgical instruments so that they are visible not only in the endoscopic image but also in the ultrasound image. For example, it has been proposed to place ultrasound transducers on the surgical instrument so that it is possible to detect the instrument with the ultrasound imaging device, and optionally permit readjustment between the endoscopic image and the ultrasound image for merging of endoscopic and ultrasound data with a view to obtaining an enhanced image. However, said solution is time-consuming since processing of the data is complex which means that viewing of the enhanced images cannot be made in real time.
Another solution with which to relate and cross-map endoscopic images and ultrasound images is to use an optic locator placed outside the patient so that it can view both the endoscopic camera and the ultrasound probe, then triangulation can be used to readjust the acquired endoscopic and ultrasound images on the basis of the relative position of the external parts of the endoscopic camera and ultrasound probe. However, said solution cannot be implemented under any surgical conditions since it must be possible to visualize both imaging devices. In addition, said system is relatively voluminous which is a major drawback regarding required operating room space.
One purpose of the present invention is to propose an imaging system for the monitoring of a surgical instrument in an operative site inside a cavity of the body of an animal; in particular in a human being, with which it is possible to solve at least one of the above-cited disadvantages.
One purpose of the present invention is in particular to propose a system with which it is possible to visualize enhanced images in close to real time, even in real time.